A conventional computer keyboard is configured with a plurality of key switches, each of which moves straight down and then returns straight up in response to a user's push operation. For miniaturization, it is desired to reduce the overall thickness of the keyboard. Therefore, there would be limited travel distance for keystroke. However, thickness reduction over a certain level, for example, from 2 mm to 1 mm of the travel distance, will adversely affect the tactile recognition of a user while hitting the keys.